ATI’s upcoming RV560 and RV570 will find its way into single-board, dual-GPU CrossFire configurations. Since the GPU cores have integrated composite engines, the cards are capable of Crossfire support directly on the card.

ATI is recommending to its AIB partners that the new 80nm mainstream and value parts will be joined together on a single PCB with a PLX Technology ExpressLane PEX 8532 PCI Express bridge chip. This bridge chip is currently used on ATI Gemini graphics cards such as the GeCube dual X1600 graphics card. The bridge chip itself is nearly the same size as the GPU but only draws approximately 7.38 watts. Preliminary boards show the PEX 8532 heatsink-less which isn’t surprising considering its low power draw.

On Gemini graphics boards the PEX 8532 bridge chip (PDF) takes one PCI Express x16 interface and divides the bandwidth in half. This allocates eight PCI Express lanes to each GPU similar to how some motherboards divide sixteen PCI Express lanes across two slots on Intel, lower end SLI and CrossFire motherboards. As the PEX 8532 is a generic PCI Express switch it can be used for other implementations besides graphics switching also.

DailyTech has learned Hightech Information Systems (HIS) has dual RV570 products in the pipeline using the PEX 8352 bridge chip. Although RV570 won’t necessarily offer as much horsepower as a Radeon X1900XT, Gemini variants will be able to dedicate one RV570 GPU to physics processing; essentially one GPU can be used for graphics while the second can be used for physics or graphics. Additionally, up to four DVI outputs can be used per card with the help of twin DMS59 interfaces.

quote: 1. Single card tat features dual midrange gpu, that is not capable of competing with X1900XT???

That's not really determinable yet, although likely.

quote: 2. If that is the case, the argument is 1 gpu for graphics and the other for physics???

Yes that is specifically what the target market for this card seems to be when it starts using the RV560/RV570 ASIC.

quote: 3. Does the motherboard need to be Crossfire-ready since the crossfire chip/bridge is already integrated into the card???

Right now, yes.

quote: 4. It shares the bandwidth of the PCI Express x16, meaning each gpu gets x8 only??? Or does this apply only to the Gemini board, not the new dual gpus???

Gemini is just a name for the project ATI has for putting two GPUs on a single board. RV560 and RV570 are not dual core, they are just ASIC replacements for existing ATI chips. But yes, there is only x8 lanes per GPU, if that even really matters. Mid-range GPUs, even high-end GPUs, do not have many cases where they can push the bandwidth of the full x16 bus.